HighLow,
Yup, that pretty much covered it with my wife. She was just inside the 3 year mark so told to resign.
The interesting thing about it is that it is at odds (as we understood it, and as it was explained to us by a sympathetic HR person) with national law which apparently says that a company must provide maternity to any woman who has worked a minimum of 1 year.
But the rules here are 'flexible' at times.......